when you somke a large amount of pot in a short amount of time. usually before going to any scheduled or organized event that does not allow pot smoking (which should be most).
Dude, let's power smoke this before we get to karaoke.
When sharing a joint or blunt with friends, calling a "power smoke" changes the smoking rhythm. Instead of *puff puff pass* it's simply *puff pass*. Anybody in the circle can call a power smoke at anytime (usually nearing the end of the joint or blunt when it starts to release harsher smoke)
Dude 1: This joint is hitting hard, man. Power smoke.
Dude 2: *takes one hit* *pass*
Dude 3: *takes one hit* *pass*
Dude 1: *takes one hit* *pass*